This is a Pediatric AIDS Clinical Trials Group (PACTG)-sponsored multicenter, open-label study to establish the optimal dose of intravenous interleukin-2 (IL-2) in HIV-infected children (Part A) and to define the immunologic effects of IL-2 given intravenously for 5 days every eight weeks for 6 cycles (Part B). Immunologic parameters include CD4 and CD8 cell counts, lymphocyte proliferation to mitogens and antigens, lymphocyte apoptosis, and cytotoxic T lymphocyte precursor frequency. The dose-escalation phase (Part A) of the study has been completed, and Part B has been enrolled fully. Subjects enrolled in Part B have received 2-4 cycles of IL-2. It will take approximately 12 months to complete Part B and perform the data analysis. Preliminary results provided useful information for the design of a recently opened PACTG-sponsored study of subcutaneous IL-2.